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https://issues.apache.org/jira/browse/KAFKA-7660?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16704243#comment-16704243
]
ASF GitHub Bot commented on KAFKA-7660:
---------------------------------------
guozhangwang closed pull request #5974: KAFKA-7660: Fix child sensor memory leak
URL: https://github.com/apache/kafka/pull/5974
This is a PR merged from a forked repository.
As GitHub hides the original diff on merge, it is displayed below for
the sake of provenance:
As this is a foreign pull request (from a fork), the diff is supplied
below (as it won't show otherwise due to GitHub magic):
diff --git a/clients/src/main/java/org/apache/kafka/common/metrics/Metrics.java
b/clients/src/main/java/org/apache/kafka/common/metrics/Metrics.java
index a6da9f90397..9e2b6f18f0c 100644
--- a/clients/src/main/java/org/apache/kafka/common/metrics/Metrics.java
+++ b/clients/src/main/java/org/apache/kafka/common/metrics/Metrics.java
@@ -41,6 +41,8 @@
import java.util.concurrent.ThreadFactory;
import java.util.concurrent.TimeUnit;
+import static java.util.Collections.emptyList;
+
/**
* A registry of sensors and metrics.
* <p>
@@ -446,6 +448,9 @@ public void removeSensor(String name) {
removeMetric(metric.metricName());
log.debug("Removed sensor with name {}", name);
childSensors = childrenSensors.remove(sensor);
+ for (final Sensor parent : sensor.parents()) {
+ childrenSensors.getOrDefault(parent,
emptyList()).remove(sensor);
+ }
}
}
}
diff --git a/clients/src/main/java/org/apache/kafka/common/metrics/Sensor.java
b/clients/src/main/java/org/apache/kafka/common/metrics/Sensor.java
index ccbe8aad9cd..1af9419bc75 100644
--- a/clients/src/main/java/org/apache/kafka/common/metrics/Sensor.java
+++ b/clients/src/main/java/org/apache/kafka/common/metrics/Sensor.java
@@ -22,7 +22,6 @@
import org.apache.kafka.common.utils.Utils;
import java.util.ArrayList;
-import java.util.Collections;
import java.util.HashSet;
import java.util.LinkedHashMap;
import java.util.LinkedList;
@@ -32,6 +31,9 @@
import java.util.Set;
import java.util.concurrent.TimeUnit;
+import static java.util.Arrays.asList;
+import static java.util.Collections.unmodifiableList;
+
/**
* A sensor applies a continuous sequence of numerical values to a set of
associated metrics. For example a sensor on
* message size would record a sequence of message sizes using the {@link
#record(double)} api and would maintain a set
@@ -133,6 +135,10 @@ public String name() {
return this.name;
}
+ List<Sensor> parents() {
+ return unmodifiableList(asList(parents));
+ }
+
/**
* Record an occurrence, this is just short-hand for {@link
#record(double) record(1.0)}
*/
@@ -291,7 +297,7 @@ public boolean hasExpired() {
}
synchronized List<KafkaMetric> metrics() {
- return Collections.unmodifiableList(new
LinkedList<>(this.metrics.values()));
+ return unmodifiableList(new LinkedList<>(this.metrics.values()));
}
/**
diff --git
a/clients/src/test/java/org/apache/kafka/common/metrics/MetricsTest.java
b/clients/src/test/java/org/apache/kafka/common/metrics/MetricsTest.java
index 3184aeb8260..98b468afc3d 100644
--- a/clients/src/test/java/org/apache/kafka/common/metrics/MetricsTest.java
+++ b/clients/src/test/java/org/apache/kafka/common/metrics/MetricsTest.java
@@ -16,6 +16,8 @@
*/
package org.apache.kafka.common.metrics;
+import static java.util.Collections.emptyList;
+import static java.util.Collections.singletonList;
import static org.junit.Assert.assertEquals;
import static org.junit.Assert.assertFalse;
import static org.junit.Assert.assertNotNull;
@@ -202,6 +204,20 @@ public void testBadSensorHierarchy() {
metrics.sensor("gc", c1, c2); // should fail
}
+ @Test
+ public void testRemoveChildSensor() {
+ final Metrics metrics = new Metrics();
+
+ final Sensor parent = metrics.sensor("parent");
+ final Sensor child = metrics.sensor("child", parent);
+
+ assertEquals(singletonList(child),
metrics.childrenSensors().get(parent));
+
+ metrics.removeSensor("child");
+
+ assertEquals(emptyList(), metrics.childrenSensors().get(parent));
+ }
+
@Test
public void testRemoveSensor() {
int size = metrics.metrics().size();
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> Stream Metrics - Memory Analysis
> --------------------------------
>
> Key: KAFKA-7660
> URL: https://issues.apache.org/jira/browse/KAFKA-7660
> Project: Kafka
> Issue Type: Bug
> Components: metrics, streams
> Affects Versions: 2.0.0
> Reporter: Patrik Kleindl
> Priority: Minor
> Attachments: Mem_Collections.jpeg, Mem_DuplicateStrings.jpeg,
> Mem_DuplicateStrings2.jpeg, Mem_Hotspots.jpeg, Mem_KeepAliveSet.jpeg,
> Mem_References.jpeg, heapdump-1543441898901.hprof
>
>
> During the analysis of JVM memory two possible issues were shown which I
> would like to bring to your attention:
> 1) Duplicate strings
> Top findings:
> string_content="stream-processor-node-metrics" count="534,277"
> string_content="processor-node-id" count="148,437"
> string_content="stream-rocksdb-state-metrics" count="41,832"
> string_content="punctuate-latency-avg" count="29,681"
>
> "stream-processor-node-metrics" seems to be used in Sensors.java as a
> literal and not interned.
>
> 2) The HashMap parentSensors from
> org.apache.kafka.streams.processor.internals.StreamThread$StreamsMetricsThreadImpl
> was reported multiple times as suspicious for potentially keeping alive a
> lot of objects. In our case the reported size was 40-50MB each.
> I haven't looked too deep in the code but noticed that the class Sensor.java
> which is used as a key in the HashMap does not implement equals or hashCode
> method. Not sure this is a problem though.
>
> The analysis was done with Dynatrace 7.0
> We are running Confluent 5.0/Kafka2.0-cp1 (Brokers as well as Clients)
>
> Screenshots are attached.
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